The invention relates to a device for therapeutical treatment of a blood vessel.
U.S. Pat. No. 5,078,736 describes a stent which can be introduced into a blood vessel by means of a balloon catheter and which can be expanded radially to engage the inside surface of the blood vessel in order that the stent after withdrawal of the balloon catheter from the blood vessel will be left in the expanded condition thereof as an inside lining in the blood vessel. The stent comprises an electrically conducting socket which can be heated when located in the blood vessel, by means of an extra-corporeally located power source in order to provide an intended therapeutic effect in the blood vessel.
In one embodiment this heating is effected inductively i.e. without wire connection between the stent and the power source. Since the stent has a small mass a powerful coil is, however, required for heating the stent to the necessary temperature inductively and it may even be necessary to allow the induction coil to operate at such a high power that water cooling thereof may be necessary, which makes the device expensive in manufacture and also cumbersome in use.
The purpose of the invention is to provide a much more easily handled device for wireless external influence on the stent, and for this purpose the invention provides a device of the kind referred to above with the features of claim 1.
The use of ultrasound for therapeutic purposes is known per se. E.g. GB-A-2 126 901 discloses an ultrasound hyperthermia applicator for heating relatively large tissue. volumes by ultrasound energy.
The invention also relates to a method for therapeutic treatment of a blood vessel comprising the steps of inserting a stent into the blood vessel by means of a balloon catheter, expanding the stent by means of the balloon catheter to engagement with the inside surface of the blood vessel, withdrawing the balloon catheter from the blood vessel, the expanded stent being left in the blood vessel in engagement with the inside surface thereof, and exposing the stent left in the blood vessel to an extra-corporeally generated ultra-sound field in order to provide a therapeutical effect in the blood vessel in the region of the stent.